Method and apparatus for analyzing a golf stroke

ABSTRACT

A method of analyzing and practicing golf strokes, such as putting strokes, is provided. A surface is provided, wherein a golfer can practice one or more strokes in an environment simulating components of a golf course, such as a green. A club movement detector embedded in the surface and comprising a plurality of photodetectors and associated circuitry determines the position and velocity of the club face A head movement sensor detects rotational movement of the golfer&#39;s head during the golf stroke. An eye movement sensor detects movement of the eyes of the golfer during the golf stroke. A processor connected to the club movement sensor, eye movement sensor, and head movements sensor gathers movement data during the golf stroke and produces measurements corresponding to the golf stroke, such as eye, head, and club movement of the golfer. The invention includes measuring head movement data and wirelessly transmitting same for remote analysis during a golf stroke. Club head movement is sensed by an infrared ranger placed along a line perpendicular to the face of the clubhead. Eye, head, and club movement data can be combined into one or more serialized data streams, and transmitted wirelessly over one or more RF channels for remote reception and processing. Finger, wrist, and elbow movements can also be measured and analyzed during a golf stroke or a free throw setting.

RELATED APPLICATIONS

[0001] This application is a continuation-in-part application of U.S.Patent Application Serial No. 10/107,910, filed Mar. 27, 2002, now U.S.Pat. No. _______, issued ______, which is related to and claims thebenefit of the U.S. Provisional Application Serial No. 60/296,527 filedJun. 7, 2001, and U.S. Provisional Application Serial No. 60/317,944filed Sep. 10, 2001. This application is also a continuation-in-partapplication of PCT Application Serial No. PCT/US02/18243 filed Jun. 7,2002, which is related to and claims the priority of U.S. PatentApplication Serial No. 10/107,910 filed Mar. 27, 2002, now U.S. Pat. No.______, issued _______, and U.S. Provisional Application Serial No.60/371,699 filed Apr. 11, 2002. The entire disclosures of all of theserelated applications are expressly incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a method and apparatus for golfstroke analysis, and more particularly, to a method and apparatus foranalyzing components of a golf stroke including club face movement andthe physical movement of a golfer during a stroke. The present inventionalso relates to a method and apparatus for allowing golfers to practiceand improve their golf strokes.

[0004] 2. Related Art

[0005] In the field of sports, generally, and in the game of golf,particularly, there has been an increasing need to address specificquestions posed by athletes concerning the body's forces and motionsduring athletic activities. Much information has been acquired about thegolf swing and the physical forces associated therewith, includingforces impacting the golf ball. Such information has been obtained usinghigh-speed photography and videotape, and the components of the golfswing have been studied in great detail during, at least, the past 50years. Unfortunately, such methodologies do not allow for real-timeanalysis of a golfers'stroke.

[0006] The putting stroke is a crucial element in the game of golf.Statistics compiled by the Professional Golfer's Association show thatapproximately 40% of the total strokes by professional golfers in agiven round are spent on putting. Golf teaching professionals and sportspsychologists frequently teach beginning and experienced golfers theimportance of minimal or no eye and head movements throughout theputting stroke. Reduced eye movement is particularly important tosuccessful execution of the putting stroke, because eye fixation atlocations other than the ball can cause improper strokes and missedputs. Further, reduced head movement allows a golfer to maintain astable image of a putting surface, thereby enhancing the golfer'saccuracy at putting. If the golfer's head moves during the stroke,putting misalignment and missed putts can result. Additionally, putterhead velocity and acceleration, in conjunction with a golfer's grip, areuseful indicators of a golfer's putting accuracy and ability.

[0007] What would be desirable, but has not yet been provided, is asystem for analyzing the aforementioned aspects of a golfer's puttingstroke, and producing real-time results indicating the effectiveness andaccuracy of the putting stroke, and for allowing golfers to practicetheir strokes while also receiving feedback information.

OBJECTS AND SUMMARY OF THE INVENTION

[0008] It is an object of the present invention to provide a method andapparatus for analyzing golf strokes

[0009] It is another object of the present invention to provide a methodand apparatus for analyzing putting strokes.

[0010] It is an additional object of the present invention to provide amethod and apparatus for allowing a golfer to practice and improve hisor her golf stroke, while receiving feedback thereon and allowing forthe comparison of measurements of the swing to measurements of aprofessional golfer's swing.

[0011] It is a further object of the present invention to provide amethod and apparatus for measuring eye, head, and club movement during agolf stroke, including a putting stroke.

[0012] It is an additional object of the present invention to provide amethod and apparatus for analyzing a golf stroke including a clubmovement sensor for measuring club movement.

[0013] It is still another object of the present invention to provide amethod and apparatus for analyzing a golf stroke including a headmovement sensor for measuring head movements during the stroke.

[0014] It is a further object of the present invention to provide amethod and apparatus for analyzing a golf stroke including an eyemovement sensor for measuring eye movements during the stroke.

[0015] It is another object of the present invention to provide a methodand apparatus for analyzing a golf stroke including a processor foracquiring eye, head, and club movement data and processing same.

[0016] It is still another object of the present invention to provide amethod and apparatus for comparing eye, head, and club movement data ofa golfer to eye, head, and club movement data of golfers of variousexperience levels.

[0017] It is yet another object of the present invention to provide amethod and apparatus for determining the effect of different golf gripson eye, head, and club movement during a golf stroke, including aputting stroke.

[0018] The present invention relates to a method and apparatus foranalyzing and practicing a golf stroke, particularly a golf puttingstroke. A putting platform is provided, wherein a golfer can putt in anenvironment simulating a golf green. Information regarding the golfer'seye, head, and club movements during the putting stroke are acquiredusing a plurality of sensing devices. A club movement sensor in theputting surface measures club movements during the stroke, withoutrequiring attachment to the club. Eye movement sensors measure left andright eye movements of the golfer during putting. A head movement sensortracks rotational movement of the golfer's head during the puttingstrokes. The acquired motion data are gathered simultaneously by aprocessor, and time traces of club, head, and eye movement may begenerated. The time traces can be compared to time traces of golfers ofvarious experience levels to determine the accuracy and efficiency ofthe golfer's putting stroke. Additionally, the effect of various golfinggrips on eye, head, and club movement can be measured and analyzed. Assuch, a golfer can practice and improve his or her golf stroke, andcompare measurements thereof to measurements of others, such asprofessionals.

[0019] In an embodiment of the present invention, eye, club, and headmovement information is monitored by a plurality of sensors including aninfrared club movement sensor, an infrared eye movement sensor, and anaccelerometer for measuring head movement. The infrared club movementsensor is placed behind the golf club and along the swing path of theclub. An infrared beam is projected from the sensor and bounces off of areflective back portion of the clubhead. The reflected beam is receivedby the sensor, and the distance of the clubhead from the sensor ismeasured. The measured distance is utilized to calculate clubheadmovement. Information from the sensors can be transmitted by wire, orwirelessly through one or more RF channels.

[0020] Output from the sensors of the present invention is gathered andprocessed by a plurality of controllers. The controllers interact toprovide a single serialized data stream having information correspondingto head, eye, and putter movement. The data stream can be transmittedwirelessly over one or more RF channels, and can be remotely receivedfor processing. Additionally, finger, wrist, and elbow movement can bemeasured during a golf stroke or a free throw, processed by a controllerto produce a serialized data stream, and transmitted wirelessly forremote reception and processing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other important objects and features of the invention will beapparent from the following Detailed Description of the Invention takenin connection with the accompanying drawings in which:

[0022]FIG. 1 is a perspective view of the apparatus of the presentinvention during use by a golfer.

[0023]FIG. 2a is a top view of the club movement sensor shown in FIG. 1.

[0024]FIG. 2b is a side view of the club movement sensor and a portionof the putting surface shown in FIG. 1.

[0025]FIG. 2c is an end view of the club movement sensor and a portionof the putting surface shown in FIG. 1.

[0026]FIG. 3 is a perspective view of an embodiment of the head movementsensor shown in FIG. 1.

[0027]FIG. 4a is a side view of the eye movement sensor shown in FIG. 1.

[0028]FIG. 4b is a side view showing the eye movement sensor of FIG. 1shown in greater detail.

[0029]FIG. 5 is a block diagram showing components of the presentinvention.

[0030]FIG. 6 is a schematic diagram showing a circuit configuration ofthe club movement sensor of the present invention.

[0031]FIG. 7 is a diagram showing operation of the club movement sensor.

[0032]FIG. 8 is a graph showing a time trace of club movement during aputting stroke.

[0033]FIG. 9 is a graph showing a time trace of eye movement during aputting stroke.

[0034]FIG. 10 is a graph showing a time trace of head movement during aputting stroke.

[0035]FIG. 11a is a graph showing a time trace of club movement of anexperienced golfer during a putting stroke.

[0036]FIG. 11b is a graph showing a time trace of club movement of anovice golfer during a putting stroke.

[0037]FIG. 12 is a graph showing simultaneous time traces of eye, head,and club movement during a putting stroke.

[0038]FIG. 13a is a graph showing simultaneous time traces of eye, head,and club movement of a novice golfer during a putting stroke.

[0039]FIG. 13b is a graph showing simultaneous time traces of eye, head,and club movement of an experienced golfer during a putting stroke.

[0040]FIG. 14 is a graph showing time traces of eye, head, and clubmovement when a conventional golf grip is used during a putting stroke.

[0041]FIG. 15 is a graph showing time traces of eye, head, and clubmovement when a cross-handed golf grip is used during a putting stroke.

[0042]FIG. 16 is a graph showing time traces of eye, head, and clubmovement when a one-handed golf grip is used during a putting stroke.

[0043]FIG. 17 is a table showing results of statistical analysis ofconventional, cross-hand, and one-handed grips used during 3 foot and 9foot putts.

[0044]FIG. 18 is a photograph showing an embodiment of the presentinvention for analyzing head movement during a golf stroke uses anaccelerometer and that wirelessly transmits the acquired data to aprocessor.

[0045]FIG. 19 shows an embodiment of a head movement sensor of FIG. 18.

[0046]FIG. 20 is a schematic showing a circuit for use with theembodiment of the present invention shown in FIG. 18, for convertingaccelerometer output to head rotation data.

[0047]FIG. 21 is a graph showing time traces of putter, eye, and headmovement measured using the apparatus of FIG. 18.

[0048]FIG. 22a is a top view showing an alternate embodiment of the clubmovement sensor of the present invention.

[0049]FIG. 22b is a front view of the club movement sensor of FIG. 22a.

[0050]FIG. 22c is a schematic showing a circuit for filtering andprocessing output of the club movement sensor of FIG. 22a.

[0051]FIG. 23 is a diagram showing an alternate embodiment of the eyemovement sensor of the present invention.

[0052]FIG.24a is a block diagram showing a circuit according to thepresent invention for producing a combined serial data stream containingeye, club, and head movement data.

[0053]FIG. 24b is a block diagram showing a sample data stream producedby the circuit of FIG. 24a.

[0054]FIG. 25a is a schematic showing a circuit for processing finger,wrist, and elbow acceleration signals.

[0055]FIG. 25b is a block diagram showing a circuit according to thepresent invention for producing a combined serial data stream containingeye, finger, wrist, and elbow acceleration data.

[0056]FIG. 25c is a block diagram showing the circuit of FIG. 25b ingreater detail.

[0057]FIG. 26a is a view showing an apparatus according to the presentinvention for measuring finger, wrist, and elbow movement during a freethrow.

[0058]FIG. 26b is a view showing the apparatus of FIG. 26a in use duringa basketball throw.

[0059]FIG. 27 is a graph showing time traces of finger, wrist, elbow,and eye movements during a free throw.

DETAILED DESCRIPTION OF THE INVENTION

[0060] The present invention relates to a method and apparatus foranalyzing golf strokes, particularly a putting stroke. A variety ofphysical movements can be tracked and analyzed during the golf stroke,such as eye, head, and club movement, and time traces thereof can beproduced in real time. The sampled data can be compared withpre-recorded time traces of golfers at different experience levels, todetermine the accuracy and efficiency of the golfer's stroke. Further,the effects of various golf grips on eye, head, and club movement can bedetermined. A golfer can practice and improve his or her game, andcompare measurements relating to his or her golf stroke to measurementsof professionals.

[0061]FIG. 1 is a perspective view of an embodiment of the presentinvention. The system of the present invention comprises a variety ofcomponents which, operating in conjunction, provide golf strokeanalysis. A putting surface 80 is provided for a golfer 20 for takingpractice putting strokes using any club 30 and golf ball 34 known in theart. Movement of club 30 along a path generally indicated by line 32 canbe analyzed by club movement sensor 60, embedded in putting surface 80,as will be hereinafter further described. Importantly, club movementsensor 60 does not obstruct the path of golf ball 34, allowing golfer 20to putt normally and (hopefully) sink golf ball 34 into hole 82.Further, putting movement sensor 60 allows for the analysis of movementof club 30, without requiring the attachment of any apparatus thereto.

[0062] In an embodiment of the present invention, putting surface 80 canbe partitioned into two or more surfaces that can be positionedlengthwise to allow for putts of varying lengths. For example, twosections of putting surface 80 can be joined to allow for putts of threefeet in length, additional sections can be added to allow for putts ofnine feet in length Any combination of sections of putting surface 80can provided for allowing putts of any desired length.

[0063] Movement of the head of golfer 20 during the putting stroke canalso be measured by the present invention. Rotational movement of thehead of golfer 20, indicated generally along axis 24, can be measured byhead movement sensor 40, attached to helmet 41, as will be hereinafterfurther described. It is to be understood that other types of headmovement (i.e., side-to-side) are contemplated by the present inventionand considered within the scope thereof. Head movement sensor 40 can beany sensor known in the art, e.g., an accelerometer with wirelesstransmitter and receiver, that is capable of measuring rotationalmovement.

[0064] Eye movements of golfer 20 can also be analyzed by the presentinvention by eye movement sensor 50, as will be hereinafter furtherdescribed. In a preferred embodiment, eye movement sensor 50 is aninfrared device that tracks motion of both right and left eyes of agolfer Other eye movement sensors are considered within the scope of theinvention.

[0065] Movement data generated by eye movement sensor 50, head movementsensor 40, and club movement sensor 60, is transmitted to processor 70by cables 72. It is conceivable that other means for transmitting theacquired data, such as radio frequency (“RF”) or infrared (“IR”)transmission, can be utilized to channel the acquired movement data toprocessor 70. The movement information gathered by processor 70 during aputting stroke can then be analyzed to determine the accuracy andefficiency of the putting stroke.

[0066]FIG. 2a is a top view of the club movement sensor of the presentinvention. Putting motion sensor 60 comprises first detector array 62,and second detector array 64, each of the detectors having a pluralityof detectors 66. In a preferred embodiment of the invention, detectors66 are infrared photo transistors. As a club moves along axis 32,shadows are cast on one or more of the detectors 66, whereupon the oneor more detectors 66 turn electrically off The outputs of detectors 66of both first detector allay 62 and second detector array 64 are thenfed to processor 70 via cables 72. The second detector array 64 ispositioned to track movement of the club to impact. Thereafter, thefirst detector array 62 is positioned to track movement of the putterafter impact. The first detector array 62 is offset from the seconddetector array 64, so that golf ball 34 can travel freely along path 36without traveling over detectors 66 of first detector array 62. Otherspatial configurations of club movement sensor 60, first detector array62, and second detector array 64 are considered within the scope of thepresent invention.

[0067]FIG. 2b is a side view of the club movement sensor 60 and puttingsurface 80 of the present invention. In a preferred embodiment of thepresent invention, detectors 66 are positioned at increasing intervalsaway from the ball 34, in both frontward and rearward directions. Forexample, the first four detectors 66 of first detector array 62 andsecond detector array 64, closest to ball 34, are spaced approximately ½inch apart. The next two detectors are spaced 1 inch apart. Theremaining two detectors are then spaced 2 inches apart. It is to beunderstood that additional detectors and other spatial arrangements areconsidered within the scope of the present invention.

[0068]FIG. 2c is an end view of the club movement sensor 60 and puttingsurface 80 of the present invention. The surface 80 can be constructedof wood boards 82, 84, and 86, such as particle boards, which are joinedtogether and covered with artificial grass to form putting surface 80.Other materials capable of forming putting surface 80 are consideredwithin the scope of the present invention. Putting surface 80 containscavities for retaining embedded detector arrays 62 and 64.

[0069]FIG. 3 is a perspective view of the head movement sensor of thepresent invention. Rotational movement of a golfer's head about axis 24can be measured during a putting stroke by sensor 44. A golfer wears hator helmet 41 which transfers rotational movement of the golfer's head tosensor 44, via interconnections 42 and 43. Interconnections 42 and 43are designed to mate interchangeably, and allow a user to step away fromsensor 44 to disengage therefrom. It may be desirable to magnetize thesecomponents to facilitate engagement thereof Interconnection 42 isattached to hat or helmet 41, and interconnection 43 is attached tosensor 44. Sensor 44 can be any sensor in the art that is capable ofmeasuring rotational movement, such as a potentiomenter. According to anembodiment of the invention, sensor 44 is mounted via pivot 45 to afixed surface, and output from sensor 44 is transmitted via cables 72.It is to be understood that various other configurations are consideredwithin the scope of the invention. For example, sensor 44 could bemounted on the hat or helmet 41, and could be self-contained, i.e., notattached to a fixed surface. The sensor could contain a pendulum suchthat when one rotates his or her head, a reading is taken. Further, thisreading could be wirelessly transmitted to the processor. Additionally,other headgear can be used to receive the golfer's head and transfermovement thereof to a sensor.

[0070]FIG. 4a is a side view of the eye movement sensor 50 of thepresent invention. Eye movement sensor 50 can be any sensor known in theart that is capable of measuring eye movements, such as a Skalar-IrisModel 6500 helmet-mounted infrared reflection device. Other comparabledetection devices can be used with the present invention withoutdeparting from the scope thereof In a preferred embodiment, eye motionsensor 50 contains one or more infrared detectors 52 that are pointedgenerally in the direction of the golfer's eyes and measure eye motionof the golfer (i.e., left-to-right and right-to-left eye motion). Outputfrom the one or more infrared detectors 52 can be sent to a processorvia cables 72, or wirelessly. Optionally, eye motion sensor 50 can beaffixed to hat or helmet 41 via frame 54, or formed integrallytherewith. Alternatively, the sensors can be incorporated on eyewear.Preferably, hat or helmet 41 and eye motion sensor 50 are manufacturedto be lightweight, so that a golfer experiences minimal to no discomfortwhile wearing same during a golf stroke.

[0071]FIG. 4b is a side view showing the eye movement sensor 50 of thepresent invention shown in greater detail. Movements of a golfer's eyes,such as eye 26, can be tracked by infrared detectors 52. In a preferredembodiment of the present invention, infrared detectors 52 of eyemovement sensor 50 have a linear range of +/−25 degrees, a combinedresolution of 5 minutes of arc, and a bandwidth of 200 Hz, but thesetolerances are not required. Voltage output signals of eye movementsensor 50 represent eye movements of the golfer's eyes, and can beanalyzed by a processor.

[0072]FIG. 5 is a block diagram showing component parts of the presentinvention. Outputs from the head movement sensor 40 and eye movementsensor 50 are connected to analog-to-digital (A/D) converters 90 and 92,respectively. Club movement sensor 60 is connected to digital input port94. The resulting digital signals derived fiom each of the sensors 40,50, and 60 are then processed in real time by processor 70. Processor 70can be any computer system known in the art. In a preferred embodimentof the present invention, processor 70 acquires the digitized movementdata from each of the sensors, and outputs same. Such output maycomprise synchronized time trace plots indicating movement of the righteye, left eye, club, and head of the golfer. As shown in FIG. 5, suchdata can be output through numerous channels (i.e., channels 1 through4) for presentation to the golfer or for further data processing.

[0073]FIG. 6 is a schematic diagram showing an example of a circuitconfiguration of the club movement sensor 60 of the present invention. Aplurality of infrared sensors, such as photo transistors Q₁ throughQ_(n), can be connected to provide club movement detection. For purposesof illustration, only photo transistors Q₁ through Q₄ are shownconnected in the circuit of FIG. 6. Further, other light-sensingdevices, such as CdS photocells, can be used in place of the phototransistors. Each of photo transistors Q₁ through Q₄ are connected todifference amplifiers D₁ through D₄, which reduce noise in the signalsgenerated by each of photo transistors Q₁ through Q₄. Further,difference amplifiers D₁ through D₄ allow for the generation of anelectrical signal corresponding to the leading edge (i.e., face) of aclub passed over one or more of photo transistors Q₁ through Q₄.Connected to difference amplifiers D₁ through D₄ are comparators C₁through C₄, which compare the outputs of each of difference amplifiersD₁ through D₄ to a threshold voltage V_(T) It is to be understood thatother circuit configurations of club movement sensor 60 not depicted inFIG. 6 are considered within the scope of the present invention. In apreferred embodiment of the invention, 16 photo transistors are providedin club movement sensor 60 to produce a 16 bit digital signal in whichone of the bits indicates the position of the club face.

[0074]FIG. 7 is a diagram showing operation of the club movement sensor60. Club 30, having a face 31, is passed over photo transistors of theclub movement sensor 60, shown illustratively as Q₁ through Q₄,generally along path 32 of a putting stroke. At a given point along thepath 32 of the putting stroke, club 30 casts a shadow over one or moreof the photo transistors of club movement sensor 60, turning sameelectrically off As shown, club 30 casts a shadow over photo transistorsQ₂ and Q₃, turning them to an off state, while photo transistors Q₁ andQ₄ remain in an electrically on state. In an illustrative embodiment,the on state of the photo transistors is indicated as a voltage of 0volts, while the off state is indicated as a voltage of +5 volts.

[0075] Voltage outputs from each of photo transistors Q₁ and Q₄ are thensent to difference amplifiers D₁ through D₄, wherein outputs from two ofthe photo transistors are processed by each of the differenceamplifiers. When the input voltage of a first phototransistor connectedto one of the difference amplifiers is lower than the input voltage ofthe second phototransistor, a negative voltage is produced. Conversely,when the input voltage of the first phototransistor is lower than theinput voltage of the second phototransistor, a positive voltage isproduced. Further, when the input voltages of the photo transistors areequal, zero voltage is produced. Thus, as shown in the illustrativeembodiment of FIG. 7, voltage of zero produced by Q₁ and a voltage of +5volts produced by Q₂ cause difference amplifier D₁ to emit a voltage of−5 volts.

[0076] Outputs from each of the difference amplifiers D₁ through D₄ arethen sent to comparators C₁ through C₄, and are compared thereby to athreshold voltage V_(T). In a preferred embodiment of the presentinvention, V_(T) is 0.7 volts. Other values can be substituted forV_(T). For input voltages that fall below V_(T), a negative voltage(i.e., −12 volts) is produced. Conversely, for input voltages thatexceed V_(T), a positive voltage (i.e., +5 volts) is produced. Thus, asshown in FIG. 7, a voltage of −5 volts provided by difference amplifierD_(q), which is lower than V_(T) of −0.7 volts, an output voltage of −12volts is produced by comparator C₁. Accordingly, the position of face 31of club 30 can be indicated by a single positive voltage produced by oneof the comparators. Therefore, a voltage of +5 volts produced bycomparator C₃ indicates the position of club face 31 amongst theplurality of photo transistors.

[0077] Outputs from the sensors of the present invention can be utilizedto produce time traces corresponding to eye, club, and head movements.In a preferred embodiment of the invention, C++ and MATLAB programs areused to generate position and velocity graphs as functions of time forclub movement, left eye movement, right eye movement, and head movement.The generated time traces/graphs can then be compared amongst golfers atvarying skill levels to indicate the efficiency and accuracy of thesubject golfer. It is well known that any general purpose computer,programmed by languages known in the art, can be used to produce thetime traces.

[0078] It should be apparent to those skilled in the art that thepresent invention can be adapted to allow analysis and practice of alltypes of golf strokes, such as putting, driving strokes, iron stokes,chips, pitches, or other stokes. The apparatus of the present inventioncan be installed in commercial driving ranges, golf courses, or otherpractice locations, allowing golfers to quickly gauge the efficiency oftheir golf strokes and to receive feedback on practice strokes byreturning real-time measurements of the strokes and comparing same tomeasurements of professional golfers. Further, the present invention canbe adapted to allow practice and analysis of other sports involvingstroke-like movements.

EXAMPLE

[0079] The apparatus of the present invention was experimentally testedon twelve volunteers, divided into three groups according to skilllevels. Individuals with handicaps between 0 and 9 were placed in thefirst group, and individuals with handicaps between 10 and 20 wereplaced into the second group. Novices were placed into the third group.Each group had four volunteers. Each subject made twenty 3-foot puttsand twenty 9-foot putts using the present invention, and results foreach of the volunteers were compared. It was found that the typicallow-handicapper exhibited a small head rotation (i.e., clockwise as seenfrom top) during the backstroke, compensated for by a smooth eyemovement (i.e., vestibulo-ocular reflex), wherein steady eye fixation onthe ball was maintained. Head rotation appeared to be associated with aslight shoulder turn during the putting stroke, and occurred lessfrequently for 3-foot putts but occasionally appeared for 9-foot putts.The typical mid-handicapper demonstrated a similar response pattern, butadditionally exhibited saccadic eye movements (i.e., fast jumps infixation) during the backstroke and at the time of impact. The typicalnovice golfer showed relatively large head rotations and compensatoryeye movements, and exhibited frequent erratic eye fixations through thebackstroke and during impact.

[0080]FIGS. 8 through 10 are graphs showing examples of measurements ofclub, eye, and head movement achieved by the present invention. FIG. 8is a graph showing time traces of club movement during a putting strokeproduced by the present invention. Club position, measured incentimeters, is graphed as a function of time, measured in seconds.Positive and negative club position values indicate movements toward oraway from the hole, respectively. Position of the club is represented asa solid line, while velocity of the club is represented as a dashedline. The point of impact with the ball is illustratively represented asa club position value of 0, occurring between 1 and 1.5 seconds.

[0081]FIG. 9 is a graph showing time traces of eye movement during aputting stroke. Eye movements for both left and right eyes of thesubject are indicated in the top and bottom graphs, respectively. Priorto capturing eye movement data, the subject fixated on three knownlocations (i.e., left end, middle, and right end of the club movementsensor 60 of the present invention), in order to provide adequatecalibration data. Eye movement data acquired during the putt was thenmeasured with reference to the calibration data, and eye position wasrecorded as displacement in centimeters of the left and right eyes alongputting surface 80. The solid line of the graph indicates eyedisplacement in centimeters. Further, the dashed line indicates eyevelocity.

[0082]FIG. 10 is a graph showing a time trace of head movement during aputting stroke. Prior to acquiring head movement data, the head movementsensor 60 was pre-calibrated to provide conversion from a measuredvoltage change to a corresponding angular rotation of the potentiometershaft, which in turn corresponded to an angular rotation of thesubject's head. This angle was then converted to a displacement of ahypothetical beam emanating from the center of rotation of the head,approximated by the position of the center between the two eyes of thesubject, and measured in centimeters As shown in the graph, headposition is measured in centimeters from the center position of thehead, and indicated as a solid line. The dashed line indicates headvelocity.

[0083]FIG. 11a is a graph showing a time trace of club movement of anexperienced golfer during a putting stroke. As can be seen, clubmovement is relatively smooth, with backward and forward movement beingrelatively uniform. These results can be compared to FIG. 11b, whichshows a time trace of club movement of a novice golfer during a puttingstroke. Backward movement is noticeably larger than forward movement,and there is a lack of uniformity between forward and backwardmovements.

[0084]FIG. 12 is a graph showing simultaneous time traces of eye, head,and club movement during a putting stroke. The dotted line across thefour graphs indicates the moment in time in which the ball is struck.Thus, using the present invention, real-time plots of head, club, andeye movement can be generated simultaneously and compared.

[0085]FIG. 13a is a graph showing simultaneous time traces of eye, head,and club movement of a novice golfer during a putting stroke. The pointof contact between the club face and the ball is represented in thegraphs as occurring after 2 seconds. As can be seen from the graphs, aconsiderable amount of eye movement for both the left and right eyes ofthe subject occurred prior to the point of contact. Further, forward andbackward club movements are not uniform, as there is greater backwardmovement than forward movement. Additionally, the occurrence of saccadiceye movement can be seen occurring prior to the putt.

[0086]FIG. 13b is a graph showing simultaneous time traces of eye, head,and club movement of an experienced golfer during a putting stroke. Ascan be seen, club, eye, and head movements for the experienced golferappeared more uniform than the movements of the novice golfer, as shownin FIG. 13a. Club movements are also more uniform, with backward andforward movements being generally equal. Eye movements are significantlyless than those of the novice golfer, and saccadic movements do notappear prior to contact between the club face and the ball.Additionally, head movement is reduced.

[0087] The present invention can also be utilized to determine theeffect of various golf grips on putting performance. For example, club,eye, and head movements can be measured and compared for various golfgrips, i.e., conventional, cross-hand, and single-hand grips. Resultsusing these grips are shown in FIGS. 14-16.

[0088]FIG. 14 is a graph showing time traces of eye, head, and clubmovement when a conventional golf grip is used during a putting stroke.Time traces of club, eye, and head movements are shown for a typical 9foot put using a conventional golf grip. For all traces, position andvelocity are indicated by solid and dashed lines, respectively. Thevertical dashed lines indicate the duration of the putt starting fromthe beginning of the backstroke and ending at the point of impact withthe ball. FIG. 15 is a graph showing time traces of eye, head, and clubmovement when a cross-handed golf grip is used during a putting stroke.FIG. 16 shows time traces using the one-handed grip.

[0089] The results shown in FIGS. 14-16 can be analyzed usingstatistical methods to determine the effect of the various grips onputting. FIG. 17 shows results of statistical analysis of conventional,cross-hand, and one-handed grips used during 3 feet and 9 feet putts.The results show differences between the putting grips for variousparameters, including height to the subject's eyes, putt amplitude, puttduration, percentage of putts made, and STD of left eye, right eye, andhead movements. To determine whether the difference between the resultsin adjacent columns are significant (i.e., p<0.1; H=1), one-tailedt-tests were performed.

[0090] Height to the subject's eyes was highest for one-handed grips,intermediate for conventional grips, and lowest for cross-handed grips.This can be attributed to the fact that one-handed subjects tended tostand more erect. Conversely, for cross-handed grips, the left hand ispositioned lower on the club grip, thus lowering the left shoulder. Sucha result tends to bring the head of the subject down as well, thuslowering the height of the head relative to the platform. The resultsfor this category are the same for 3 and 9 foot putts.

[0091] Putt amplitude is not significantly different for the threeputting grip styles for 3 foot putts. However, for 9 foot putts,amplitude for cross-handed grips are statistically significantly smallerthan for either conventional or one-handed grips. This may beattributable to a restriction of right elbow motion in the backstroke,due to increased bending of the right elbow to compensate for a higherright hand position on the club.

[0092] Putt duration is longer for the one-handed grip than for eitherconventional or cross-handed grips, for both 3 and 9 foot putts. Thismay be due to the increased length of the swing arm (i.e., club plushand and arm), in the one-handed putt. Hence, if one considers this as apendulum motion, the increased length corresponds to an increase in theperiod of motion, resulting, in turn, in an increase in the duration ofthe putt.

[0093] The percentages of putts made appear to be higher forcross-handed grips than for either conventional or one-handed grips, forboth 3 and 9 foot putts. However, such comparisons are not statisticallysignificant, except for 9 foot putts where the percentage made isstatistically significantly higher for cross-handed grip than forconventional grip (p=0.006).

[0094] The STD of combined right and left eye movements is lowest forone-handed grips, intermediate for cross-handed grips, and highest forconventional grips, for both 3 and 9 foot putts. The results are allstatistically significant except for the comparison between cross-handedand conventional grips for 3 foot putts (p=0.312).

[0095] The STD of head movements is lower for one-handed grips,intermediate for crosshanded grips, and highest for conventional grips,for 3 foot putts. These results are statistically significant except forthe comparison between one-handed grips and cross-handed grips(p=0.151). However, for the 9 foot putts, there are no statisticallysignificant differences among the putting grip styles. These findingssuggest that head motion plays a more important role in shorter (i.e., 3foot) putts than for longer (i.e., 9 foot) putts. Further, the resultsindicate that one-handed grips, and to a lesser extent, cross-handedgrips, result in less head motion during the putt.

[0096]FIG. 18 is a photograph showing an embodiment of the presentinvention for analyzing head movement during a golf stroke using anaccelerometer and wirelessly transmitting the acquired data. Aspreviously mentioned, the present invention can be implemented using oneor more devices for wirelessly transmitting head and eye movement dataduring the stroke, thereby obviating the need for interconnecting cablesbetween the head and eye movement sensors and other apparatuses. Forexample, as shown in FIG. 18, the present invention can be modified toprovide a system 100 for wirelessly measuring head movement data duringa golf stroke. The system 100 includes a helmet 110, similar in designto the helmet 41 of FIG. 1. The word “helmet” is meant to cover anysuitable mechanism for support sensing equipment including, but notlimited to, a hat, a headband that fully or partially surrounds thehead, a visor, etc. Attached to the helmet 110 are a head movementsensor 120, a battery back 130, and eye movement sensors 140.

[0097] Head movement sensed by sensor 120 is wirelessly transmitted toreceiver 160, for remote analysis. Advantageously, the sensor 120 allowsfor the untethered acquisition and analysis of head movement data duringa golfer's putting stroke, without requiring the golfer to align his orher head with a stationary device and keep same in place duringmeasurement. Head movement sensor 120 comprises an accelerometer,transmitter, and associated circuitry for measuring head movement andtransmitting same wirelessly to receiver 160 for remote analysis. Anyother device that can be used to acquire head rotation data isconsidered to be within the scope of the present invention. Batterypacks 130 and 150 can be used to provide a power source to power sensor120 and receiver 160. A 3 volt power source has been found to besufficient.

[0098]FIG. 19 shows the head movement sensor 120 of the presentinvention in greater detail. The sensor 120 comprises an accelerometer121, a transmitter 125, an antenna 126, and a power source 130. Thesecomponents can be mounted on one or more circuit boards. As shown inFIG. 19, two circuit boards are interconnected. The power source 130 isshown remote from the circuit boards but could be positioned thereon. Asshown in FIG. 19, the accelerometer 121 is mounted on one of the boards,and the wireless transmitter 125 and antenna 126 on the other board.

[0099] In a preferred embodiment of the present invention, theaccelerometer comprises an ADXL202 single chip accelerometermanufactured by Analog Devices, Inc., which provides a 167 Hzrectangular wave signal having a duty cycle proportional to theacceleration. The duty cycle represents the ratio of the pulse-width tothe period, and is proportional to the acceleration of the device ineach of two sensitive axes (i.e., X and Y axes). The dimensions of thedevice are 10.6 mm×9.9 mm×5.5 mm. Two outputs are provided, based onsensors aligned in the X and Y directions within the plane of thedevice. The device is useful for measuring tilt, and it uses the forceof gravity as an input vector to determine orientation of an object inspace. A particular axis (i.e., X or Y axis) is most sensitive totilting deviations when the device is parallel to the earth's surface.The accelerometer is capable of measuring both dynamic acceleration(i.e., vibration) or static acceleration (i.e., gravity). It is to beunderstood, however, that other devices capable of measuring headmovement are considered within the scope of the invention and may beutilized without departing from the spirit of the invention.

[0100] If the accelerometer 121 is positioned on top of a subject's headand oriented in such a way that the Y-axis of the accelerometer ispointed toward the sky and in the direction behind the subject, then theX-axis is approximately parallel to the earth's surface (and parallel toan imaginary line drawn between the two eyes), providing sensitivity totilt of the X-axis. The tilt of the X-axis is a result of the rotationof the head. Indeed, in testing the device during putts, it was foundthat the X-axis is much more sensitive to rotational as opposed totranslational (i.e., side-to-side) motions of the head. Thus, theaccelerometer can be used to measure head rotation during a golf swingor a putting stroke.

[0101] Preferably the transmitter 125 is the TR-1000 916.50 MHz hybridtransceiver manufactured by RFM, Inc. The device is well-suited toshort-range wireless data applications, can serve as either atransmitter or a receiver, and its dimensions are 10.2 mm×7.1 mm×2.0 mm.The transmitter can operate using either on-off keying (OOK) oramplitude-shift keying (ASK). The operation of the transmitter isbasically transparent to the other components of the overall device. Theinput analog signal to the transmitter is directly reflected in theoutput analog signal of the receiver. The distance between thetransmitter and receiver can be up to 100 ft depending on environmentalconditions. Thus, the transmitter/receiver combination can be easilyimplemented in a laboratory, pro-shop or driving-range environment. Itis to be understood, however, that other transmitters/transceivers knownin the art can be utilized with the present invention.

[0102] Sensor 120 can be implemented as follows the accelerometer 121can be soldered onto a small circuit board 122 (2.5 mm×4.0 mm), andappropriate components such as capacitors and resistors can be added.The transmitter 125 can be soldered onto another similar-size circuitboard 124. The two boards 122 and 124 can be mated by means of male andfemale complementary connectors on the two circuit boards. Of course, asingle board could be used. The sensor 120 can then be adhered to asmall flat plastic member that is glued to a stem. The stem can then bescrewed onto a female stem fixed on the helmet 110 of FIG. 18. Theorientation of the sensor 120 is adjusted so that the X-axis of theaccelerometer is approximately parallel to a hypothetical line drawnbetween the subject's eyes. The accelerometer signal is input to thetransmitter, which then emits a radio frequency signal. The signalconsists of a rectangular wave whose duty cycle is proportional to thehead rotation acceleration. The receiver 160 of FIG. 18 receives thesignal and relays the duty cycle signal to remote processing circuitry.Clearly, the construction of the sensor 120 can be simplified inaccordance with what is known in the art.

[0103] When the duty cycle is received by receiver 160, it is necessaryto process same to provide a signal corresponding to head movement data.An illustrative circuit 200 for providing such processing is shown inthe schematic of FIG. 20. The received duty cycle signal is fed intoinput 205 of circuit 200. In stage 210, the signal is integrated toprovide an acceleration signal corresponding to rotational accelerationof the subject's head during a putting stroke. Then, in stage 220, thesignal is fed through a biasing and gain stage to permit adjustment ofcircuit 200 to the most sensitive level (i.e., by tweaking thepotentiometer of stage 220). The signal is then integrated by anoperation amplifier in stage 230 to provide a velocity signal, and thenintegrated once again by another operation amplifier in stage 240 toproduce a head rotation position signal. A final gain stage 250 providesa larger head rotation voltage signal for input to a computer or othersystem for analysis and/or further processing. Thus, the circuit 200allows for the production of a head rotation position signal at output255 given a duty cycle signal at input 205. Other circuit configurationsfor providing head rotation position signals are considered within thescope of the invention.

[0104]FIG. 21 is a graph showing time traces of putter, eye, and headmovement measured using the wireless head measurement apparatus of thepresent invention. As can be seen in the bottom trace of the graph, headmovement information can be acquired by the accelerometer of the presentinvention, transmitted wirelessly, processed, and analyzed to produce atime trace of high accuracy corresponding to head position during theputting stroke. The angle of head rotation about the spine axis has beenconverted to an equivalent movement of an imaginary beam projectedperpendicularly to the face of the subject and onto the putting platformof the present invention.

[0105] It should also be noted that wireless data acquisition andtransmission equipment and techniques can be used to wirelessly transmitdata acquired by the eye movement sensors of the present invention.

[0106]FIG. 22a is a top view showing an alternate embodiment of the clubmovement sensor of the present invention. An infrared transceiver 200 ispositioned on the putting surface 80, and measures movement of the head31 of club 30. An infrared beam 210 is aimed at the clubhead 31, bouncesoff of same, and returns along path 215 where it is received bytransceiver 200. Thus, for example, movement of the clubhead 30 can bemonitored by the transceiver 200 as a golfer putts the ball 34 alongpath 36. Of course, other movements of the club 30 can be measured bythe infrared transceiver 200. Movement sensed by the transceiver 200 istransmitted as an electrical signal wirelessly or along cable 205.

[0107]FIG. 22b is a front view of the transceiver 200 of the clubmovement sensor shown in FIG. 22a. The transceiver can be positioned atany location on the surface 80, but preferably, is positioned behind theclubhead and along a line perpendicular to the clubface 31 of the club30. The transceiver 200 preferably includes an infrared LED 202 fortransmitting a beam of infrared light to the clubhead, and an infraredphototransistor 204 for receiving the beam after it has been reflectedfiom the clubhead. Preferably, the clubhead 31 includes a flat backsurface for reflecting the beam. A putter sold by Octagon Golf, Inc.under the name “Octagon” provides such a suitable surface.Alternatively, a reflector can be attached to the back of an existingputter. The received beam is converted to an electrical signal by thephototransistor 204 and sent as an analog signal via the cable 205, orwirelessly, for processing.

[0108] In a preferred embodiment of the present invention, thetransceiver 200 is the GP2Y0A02YK infrared ranger manufactured by SHARP,Inc. This sensor takes a continuous distance reading of the clubhead,and reports the distance as an analog voltage with a distance range ofapproximately 20 cm (8 inches) to 150 cm (60 inches). The rangerincludes a three wire connection for providing power to the ranger andtransmitting output voltage therefrom. Of course, any similar infrareddevice known in the art could be utilized as the transceiver 200 withoutdeparting from the spirit or scope of the present invention.

[0109]FIG. 22c is a schematic showing a circuit, indicated generally at210, for filtering and processing output of the putter movement sensorof FIG. 22a. As mentioned previously, output from the transceiver 200 isin the form of an analog voltage corresponding to the distance of theclubhead from the transceiver. The output signal is provided via cable205, or wirelessly, and is fed to a lowpass filter 215. The lowpassfilter 215 filters the output signal to remove any undesired noisepresent therewith. The filtered signal is then sent from lowpass filter215 to voltage follower 220. Finally, the signal is then fed to anamplifier 225, where it is amplified. The bias of the amplifier 225 canbe controlled by potentiometer 230.

[0110]FIG. 23 is a diagram showing an alternate embodiment of the eyemovement sensor of the present invention. As discussed earlier, movementof a golfer's eye 26 can be measured and processed by the presentinvention during a golfer's stroke. An infrared sensor 230 can beprovided for measuring such movement. An emitter 232 provides aninfrared beam that travels along path A and strikes a portion of the eye26. The beam is then reflected back along path B to a sensor 234. Theintensity of the beam received by the sensor 234 depends upon theportion of the eye struck by the beam, as different eye portions havedifferent reflective properties. Movement of the eye can thus bediscerned from fluctuating reflected intensities sensed by the sensor230.

[0111] In a preferred embodiment of the present invention, the sensor230 is the QRB1133 or QRB1134 reflective object sensor manufactured byFAIRCHILD SEMICONDUCTOR, Inc. The QRB1133/1134 comprises an infraredemitting diode and an NPN silicon phototransistor mounted side-by-sideon a converging optical axis in a black plastic housing. Thephototransistor responds to radiation fiom the emitting diode when areflective object passes within its field of view The device has a highsensitivity, and has an area of optimum response that approximates acircle of 0.200 inches in diameter. Of course, any suitable infraredmotion sensor known in the art could be substituted for sensor 230without departing from the spirit or scope of the present invention.

[0112]FIG.24a is a block diagram showing a circuit, indicated generallyat 250, for producing a combined serial data stream containing eye,club, and head movement data. A first controller 252 receives eye andhead movement signals that have been converted from analog to digitalformat by A/D converters. A second controller 256 receives clubheadmovement data that has also been converted from analog to digital formatby an A/D converter. The first controller 252 produces a serial datastream comprising both eye and head movement data, and forwards thestream to a first transceiver 254. The second controller 256 produces asecond serial data stream comprising clubhead movement data, andforwards same to a second transceiver 258. The first transceiver 254produces a word code, illustratively indicated as word code Z, andselectively transmits same to transceiver 258. The word code Z initiatesthe data stream generated by the second controller 256, such that thesecond serial data stream generated by the second controller 256 issynchronized with the first serial data stream generated by the firstcontroller 252.

[0113] Both the first transceiver 254 and the second transceiver 258transmit an RF signal that is received remotely by third transceiver260. The RF signal transmitted by the first transceiver 254 issynchronized with the RF signal transmitted by the second transceiver258, and contains the first serialized data stream produced by the firstcontroller 252. The second RF signal contains the second serialized datastream generated by the second controller 256. The first and second RFsignals received by the third transceiver 260 are combined to form asingle serial data stream containing eye, head, and club movement data.Preferably, the single serial data stream is compatible with the RS-232communications protocol standard, and is sent to a PC for furtherprocessing and analysis.

[0114] In a preferred embodiment of the present invention, thecontrollers 252 and 256 are the T89C51AC2 8-bit microcontroller unitmanufactured by AMTEL, Inc. The T89C51AC2 is a high-performance, flashversion of the 80C51 single chip 8-bit microcontroller, and includes a32 Kbyte flash memory block for storing programs and data. TheTC89C51AC2 includes a plurality of parallel inputs and a serial output,allowing conversion of data received at the inputs into a serializeddata stream at the serial output. Thus, as used herewith, the T89C51AC2receives at its input ports eye, head, and club movement data, andconverts same for transmission as serial data streams. Any suitablemicrocontroller known in the art can be used as controllers 252 and 256without departing from the spirit or scope of the present invention.Further, the transceivers 254, 258, and 260 are preferably the TR1000hybrid transceiver manufactured by RFM, Inc. and discussed earlier withreference to FIGS. 18-19.

[0115]FIG. 24b is a block diagram showing sample data streams producedby the circuit of FIG. 24a. As mentioned previously, the controllers 252and 256 produce serialized data streams that are synchronized with eachother and which contain eye, head, and club movement data. As shown inFIG. 24b, the first data stream represents the first serialized datastream produced by the controller 252 of FIG. 24a. The second datastream represents the second serialized data stream produced by thesecond controller 256. During operation, the first data stream isinitiated by the first controller 252 and transmitted by the firsttransceiver 254. An identifier word A is transmitted, followed by eyemovement data. Then, an identifier word B is transmitted, followed byhead movement data. A synchronizing word Z is transmitted, whereintransmission in the first data stream halts. The second data stream isthen initiated by the second controller 256 and transmitted by thesecond transceiver 258. An identifier word C is transmitted, followed byclub movement data. The second data stream is then halted, andapproximately 5 msec later, transmission of the first data streamresumes, wherein eye and head data is then transmitted in theaforementioned fashion. In this arrangement, the first and second datastreams can be received by the third transceiver 260, and combined intoa single data stream containing eye, club, and head movement data. Whilethe combination of signals provides an elegant solution, the signals canof course be sent separately.

[0116]FIG. 25a is a schematic showing a circuit, indicated generally at265, for processing finger, wrist, and elbow acceleration signals. Thepresent invention can be adapted to measure and analyze finger, wrist,and elbow movement information. Such information can be acquired duringa golf stroke, or during a free throw, such as when a ball is tossed orthrown. Other types of measurements could be acquired. The circuit 265comprises an operational amplifier (op amp) 267, to which anacceleration signal is input. The acceleration signal could be acquiredby any type of sensor (e.g., optical or electro-mechanical), and couldcomprise finger, wrist, elbow, or other type of movement data. Theamplifier 267 can be biased by a potentiometer 268, and its gaincontrolled by a fixed resistor 269 or other means. The accelerationsignal is thus amplified by amplifier 267, producing an outputacceleration signal that can be processed in accordance with the presentinvention.

[0117]FIG. 25b is a block diagram showing a circuit, indicated generallyat 270,for producing a combined serial data stream containing eye,finger, wrist, and elbow acceleration data. As discussed earlier, asingle serialized data stream comprising eye, head, and club movementdata can be produced by the present invention for analysis by a PC orother similar device. This data stream can be adapted to includeserialized eye, finger, wrist, and elbow movement data. Thus, as shownin circuit 270, a plurality of signals, such as eye, finger, wrist, andelbow acceleration/movement data, are fed to a first controller 272. Thecontroller 272 could be the aforementioned T89C51AC2 microcontroller, orother suitable substitute. The movement data is received in parallel bythe controller 272, and converted to a serial data stream. The serialdata stream is then sent to a first transceiver 274, which could be theaforementioned TR1000 transceiver or other similar substitute. The datastream is then transmitted by the first transceiver 274 via a single RFchannel, and received by the second transceiver 276 (which could also bethe TR1000 transceiver or suitable substitute). The wireless serial datastream received by the second transceiver 276 is then sent to a PC,where it can be processed by a software integration application and/oranalyzed by another application. Conceivably, time traces correspondingto finger, wrist, and elbow movement data could be generated, andcompared to predetermined time traces and/or thresholds. It should benoted that the signals corresponding to finger, wrist, and elbowmovement need not be serialized prior to transmission, and could betransmitted separately from the device.

[0118]FIG. 25c is a block diagram showing the circuit of FIG. 25b ingreater detail. As mentioned earlier, finger, wrist, elbow, and eyemovement data can be measured during a free throw. A plurality ofaccelerometers, indicated generally at 280, in addition to an eyemovement sensor 282, can be connected to the controller 272 foracquiring finger, wrist, elbow, and eye movement data during the freethrow. Preferably, the accelerometers 280 comprise a fingeraccelerometer 284, a wrist accelerometer 286, and an elbow accelerometer288, each of which produce acceleration signals that are fed to thecontroller 272 for processing in accordance with the present invention.In a preferred embodiment of the present invention, the accelerometers280 comprise the ADXL202 accelerometer chip manufactured by ANALOGDEVICES, INC., discussed earlier. Of course, any known suitableaccelerometer can be substituted without departing from the spirit orscope of the present invention.

[0119]FIG. 26a is a view showing an apparatus according to the presentinvention for measuring finger, wrist, and elbow movement during a freethrow. The apparatus, indicated generally at 300, includes a fingersensor 326, a wrist sensor 320, and an elbow sensor 314, each of whichare connected together by cable 310. The cable 310 includes a connector308 for connecting an external power source to the sensors 314, 320, and326. Preferably, a battery pack 302 delivers such power, and isinterconnected with the sensors via cable 304 and connector 306 a.Output from the sensors is fed to one or more controllers via connector306 a. Importantly, the cable 310 is flexible, conforms to a wearer'saim in use, and allows the wearer to take a free throw withoutinterfering with same. Optionally, one or more retainers 312, such asstraps or other similar retainers, can be connected to cable 310 forretaining the cable 310 against the wearer's arm.

[0120] The elbow sensor 314 comprises a first strap 316, and secondstrap 317, and a central portion 318 interconnecting the straps. Thefirst strap 316 is positionable about the upper arm of a wearer (e.g.,between the shoulder and elbow), and the second strap 317 ispositionable about the forearm of the wearer (e.g., between the elbowand wrist). Preferably, the straps 316 and 317 are adjustable toaccommodate various arm sizes, and include attachment means, such ashook-and-loop fasteners, for removably securing the sensor 314 about thewearer's elbow area. Further, the central portion 318 is flexible, andallows the straps 316 and 317 to move back and forth. When the straps316 and 317 are positioned on both the upper arm and forearm of thewearer, respectively, the central portion 318 flexes with elbow movementof the wearer during a free throw. Attached to the central portion 318is an accelerometer for measuring elbow movement during the free throw.Of course, the accelerometer could be positioned at any suitablelocation on the elbow sensor 314 for sensing elbow movement.

[0121] The wrist sensor 320 comprises a strap 322 connected to a tab324. The strap 322 is preferably positioned about the wearer's wrist.When the wearer's wrist moves, the tab 324 also moves. Attached to thetab 324 is an accelerometer for measuring wrist motion during a freethrow. Preferably, the strap 322 is adjustable for accommodating wristsof various sizes, and includes a retaining means, such as ahook-and-loop fastener, for allowing the strap to removably securedaround the wearer's wrist. During a fee throw, when a wearer's wristflexes, this motion is transferred to the accelerometer and measuredaccordingly.

[0122] Attached to an end of the cable 310 is a finger motion sensor326. Finger motion sensor 326 comprises a rearward portion 328 flexiblyor hingedly connected to a forward portion 330. The rearward portion 328includes a sleeve for allowing insertion of a wearer's finger thereinto.The forward portion 330 includes one or more finger loops, such as loops332 and 333, for allowing insertion of the wearer's finger thereinto.Optionally, a hinge 329 could be provided for hingedly attaching therearward portion 328 to the forward portion 330.

[0123] The forward portion 330 includes an accelerometer for measuringfinger motion during a flee throw. During use, the finger sensor 326 isretained against the wearer's finger by the loops 322, 333 and sleeve328. When the wearer's finger flexes, the forward portion 330 pivotswith respect to the rearward portion 328 This movement is sensed by theaccelerometer, producing measurements corresponding to fingermovemement.

[0124] It is to be understood that the foregoing description relating tomeasuring finger, wrist, and elbow movement is not limited to free throwsituations. Indeed, the apparatus 300 could be used to sense any desiredmovements in any situation. For example, finger, wrist, and elbowmovement could be sensed during an exercise routine to determine optimalexercise positions. Further, any number of accelerometers could bepositioned anywhere along the arm for measuring movemement. Theinformation acquired can be transmitted individually, or serializedaccording to the present invention and transmitted as a single datastream. Moreover, the acquired information can be transmittedwirelessly, and other sensors, such as potentiometers, could be employedwithout departing from the spirit or scope of the present invention.

[0125]FIG. 26b is a view showing the apparatus of FIG. 26a in use duringa basketball throw. In this situation, the elbow sensor 314, wristsensor 320, and finger sensor 326 are securely positioned against awearer's arm, and measure finger, wrist, and elbow movement as thewearer throws the basketball 340. The elbow sensor 314 is held inposition via the straps 316 and 317, which are preferably positionedabout the upper arm 342 and forearm 346 of the wearer, respectively. Thewrist sensor 320 is held in position via the strap 322, which ispreferably positioned about the wearer's wrist 348. The finger sensor326 is held in position via the sleeve 328. Optionally, a belt 303 couldbe provided for conveniently holding the battery pack 302 in placeagainst the wearer's hip. The cable 310 interconnects the elbow sensor314, wrist sensor 320, and finger sensor 326. The cable 310 couldoperate as a power bus, transferring power from the battery pack 302 toeach of the sensors, a data bus for culling data fiom each of thesensors, or a combination thereof (e.g., a multi-conductor or ribboncable could be employed for carrying both power and data signals). Theacquired information from the sensor can be transmitted wirelessly or ina wired configuration using a data transfer cable connected to the cable310. Further, the data from the sensors can be serialized andtransmitted as a single data stream, via wire or wirelessly.

[0126]FIG. 27a is a graph showing time traces of finger, wrist, elbow,and eye movements during a free throw. In a preferred embodiment of thepresent invention, vertical eye movement of the left eye is measuredduring the free throw, but of course, any type of eye movement from oneor both eyes could be measured and analyzed. Additionally, finger,wrist, and elbow movements are also measured and analyzed. Time tracesare produced, indicating finger, wrist, elbow, and eye movement andcomparing same to predetermined patterns. In the traces, measuredmovements are indicated by the solid lines, and predetermined patternsof an expert basketball player are indicated via the dotted lines. Thetime traces thus provide an effective basis of comparison of the user'sfree throw to that of an expert.

[0127] Having thus described the invention in detail, it is to beunderstood that the foregoing description is not intended to limit thespirit and scope thereof. What is desired to be protected by LettersPatent is set forth in the appended claims.

What is claimed is:
 1. An apparatus for analyzing golf strokescomprising: a sensor for sending a signal and receiving a reflectedsignal; a reflective surface on a golf club head for reflecting thesignal from the sensor back to the sensor; and a transmitter fortransmitting the reflected signal to a processor, wherein the processorproduces movement measurements of the golf club head during the golfstroke.
 2. The apparatus of claim 1, wherein the signal comprises aninfrared signal
 3. The apparatus of claim 2, wherein the infrared signalis generated by an infrared LED
 4. The apparatus of claim 3, wherein thereflected signal is received by an infrared phototransistor.
 5. Theapparatus of claim 1, wherein the measurements are compared tomeasurements of golfers of different skill levels.
 6. The apparatus ofclaim 1, wherein the measurements comprise time traces.
 7. The apparatusof claim 1, further comprising a second sensor for sensing head movementof the golfer during the golf stroke.
 8. The apparatus of claim 7,wherein the second sensor includes an accelerometer for measuring headmovement.
 9. The apparatus of claim 7, further comprising a third sensorfor sensing eye movement of the golfer during the stroke.
 10. Theapparatus of claim 9, wherein the third sensor comprises an infrared eyemovement detector for sensing movement of the eyes of the golfer duringthe golf stroke.
 11. The apparatus of claim 10, further comprising acontroller connected to the first, second, and third sensors forproducing a serialized data stream containing golfer movement datameasured by the sensors.
 12. The apparatus of claim 11, wherein thecontroller is connected to a transmitter and the transmitter wirelesslytransmits the serialized data stream to the processor.
 13. An apparatusfor analyzing golf strokes comprising: a first sensor for sensingmovement of a golf club head during the golf stroke; a second sensor forsensing head movement of the golfer during the golf stroke; a thirdsensor for sensing eye movement of the golfer during the golf stroke;and a transmitter for wirelessly transmitting sensed movement of thegolfer and the club head to a remote processor, the processor producingmeasurements corresponding to the movement of the golfer and the clubhead during the golf stroke.
 14. The apparatus of claim 13, wherein thefirst sensor comprises an infrared ranger.
 15. The apparatus of claim14, wherein the infrared ranger detects club head position and velocity.16. The apparatus of claim 13, wherein the first sensor produces asignal corresponding to the movement of the putter.
 17. The apparatus ofclaim 16, wherein the signal is sent to the processor for producing themeasurements.
 18. A method for analyzing golf strokes comprising:providing a golf club with a reflective back surface; positioning thetransceiver behind the golf glub and along a swing line of the club;sending signals from the transceiver towards the club; allowing thegolfer to take a stroke; receiving reflected signals from the reflectiveback surface of the club during the stroke; transmitting the receivedsignal to a processor; and producing measurements at the remoteprocessor corresponding to the movement during the golf stroke.
 19. Themethod of claim 18, further comprising sensing head movements of thegolfer during the golf stroke.
 20. The method of claim 19, furthercomprising producing measurements corresponding to the head movements ofthe golfer during the golf stroke.
 21. The method of claim 18, furthercomprising sensing eye movements of the golfer during the golf stroke.22. The method of claim 21, further comprising producing measurementscorresponding to the eye movements of the golfer during the golf stroke.23. The method of claim 18, further comprising comparing themeasurements of the golfer to measurements of golfers of different skilllevels.
 24. The method of claim 40, further comprising serializing thesensed data into a single data stream and then wirelessly transmittingthe single data stream to the processor.
 25. An apparatus for analyzingfree throw movements comprising: a first sensor for sensing fingermovement during a free throw; a second sensor for sensing wrist movementduring the free throw; a third sensor for sensing elbow movement duringthe free throw; and a processor connected to the first, second, andthird sensors for producing measurements corresponding to the finger,wrist, and elbow movements.
 26. The apparatus of claim 25, furthercomprising a controller connected to the first, second, and thirdsensors for combining sensed movements into a single data stream. 27.The apparatus of claim 26, wherein the single data stream is transmittedto the processor for processing.
 28. The apparatus of claim 26, whereinthe single data stream is wirelessly transmitted to the processor forprocessing.
 29. The apparatus of claim 25, further comprising atransmitter for wirelessly transmitting sensed movement to theprocessor.
 30. The apparatus of claim 25, wherein the measurementscomprise time traces.
 31. The apparatus of claim 25, further comprisinga fourth sensor for measuring eye movement during the free throw. 32.The apparatus of claim 31, wherein the fourth sensor measures verticaleye movement of an eye during the free throw.
 33. The apparatus of claim31, wherein sensed eye movements are wirelessly transmitted to theprocessor.
 34. A method for analyzing movement during a free throwcomprising: providing sensors for measuring finger, wrist, and elbowmovement; attaching the sensor to a wearer's finger, wrist, and elbow;allowing the wearer to take a free throw; sensing finger, wrist, andelbow movement during the free throw; and producing measurementscorresponding to sensed finger, wrist, and elbow movements.
 35. Themethod of claim 34, further comprising sensing eye movement during thefree throw.
 36. The method of claim 34, further comprising transmittingsensed movements to a processor for processing.
 37. The method of claim34, wherein the step of producing measurements comprises producing timetraces corresponding to sensed finger, wrist, and elbow movements. 38.The method of claim 37, further comprising comparing the time traces totime traces of experts.
 39. The method of claim 34, wherein the step ofsensing movements comprises sensing finger, wrist, and elbow movementduring a basketball throw.
 40. The method of claim 34, wherein the stepof sensing movements comprises sensing finger, wrist, and elbowmovements during a baseball throw.
 41. The method of claim 34, whereinthe step of sensing movements comprises sensing finger, wrist, and elbowmovements during a golf swing.